Let me ask you this-
Are normal classes easy, challenging, or really hard? If normal classes are easy or somewhat easy, then you are supposed to be in advanced classes. Advanced classes are there to be challenging, to actually make you try. And advanced classes in HS will look good to colleges and future employers. That said, if it is so hard you can't even wrap your head around anything even with your parents' and the teachers' help, then you need to talk to your parents and ask them to put you in normal classes.
For math and science, ask your parents for some help. If you can understand math first, then science should be a little easier. Maybe you could consider advanced ELA (English/Language Arts) classes. Honestly, if you're looking for classes, just do what you enjoy and what will help advance you further. If you think you are able to handle advanced classes, or you think they might be fun to try, do them. I intend on taking a Creative Writing class next year since it's something that will help in the career I want and I enjoy it. I'm also taking psychology because it's a subject I want to learn (despite the TEN-PAGE PAPER)
